1. Field of the Invention
The present invention relates to a radiation conversion device, which is driven by an on-board battery mounted internally therein, for detecting radiation that has passed through a subject and converting the radiation into image information. The invention also concerns a radiation image capturing system that utilizes such a radiation conversion device.
2. Description of the Related Art
In the medical field, a radiation image capturing apparatus, in which radiation is applied to a subject, and radiation that has passed through the subject is directed to a radiation conversion device for capturing a radiation image of the subject, has been widely used.
In this case, a radiation conversion device (electronic cassette) is disclosed, in which applied radiation is converted directly into electric signals, or after the radiation has been converted into visible light by a scintillator, a plurality of radiation detection elements made up from amorphous silicon or the like, and which are arranged in a matrix form, are used to convert the visible light into electric signals to enable reading thereof. (See, Japanese Laid-Open Patent Publication No. 2006-208306.)
In the aforementioned radiation conversion device, a transportable type of structure with a battery is known, which can be carried from place to place. In such a transportable type of radiation conversion device, electrical power from an on-board battery is consumed when the radiation image is captured. Accordingly, the transportable radiation conversion device is connected to a charging cradle for carrying out charging of the battery at appropriate times. According to the radiation conversion device disclosed in Japanese Laid-Open Patent Publication No. 2006-208306, when the radiation conversion device is connected to the charging cradle, charging of the battery is carried out, together with transmitting radiation image information via the charging cradle to an external apparatus.
Notwithstanding, according to the disclosure of Japanese Laid-Open Patent Publication No. 2006-208306, after the radiation image has been captured, because a process for transmitting the radiation information is performed after the radiation conversion device has been connected to the charging cradle, a certain amount of time is spent before the transmission process commences, and the desired radiation image information cannot be acquired quickly. Consequently, it has been considered to transmit the radiation image information immediately after capturing the image, by means of wireless communications from the radiation conversion device directly to the external apparatus.
However, there are concerns that the residual charge amount of the on-board battery mounted in the radiation conversion device may become too low, or that transmission errors may occur upon transmission of the radiation image information by wireless communications to the external apparatus. In the case that data is transmitted via wireless communications, when transmission errors occur, normally the process for transmitting the data simply is repeated or carried out again. In this case, because power from the on-board battery mounted in the radiation conversion device is used, the frequency at which charging of the battery must be performed increases undesirably.